Reliability of Functional and Diffusion MR Imaging Near Cerebral Cavernous Malformations.

BACKGROUND AND PURPOSE: Surgical resection of cerebral cavernous malformations close to eloquent regions frequently uses fMRI and DTI for surgical planning to best preserve neurologic function. This study investigates the reliability of fMRI and DTI near cerebral cavernous malformations. MATERIALS AND METHODS: Consecutive patients with cerebral cavernous malformations undergoing presurgical fMRI and DTI mapping were identified. Each cerebral cavernous malformation was hand-contoured; 2 sequential 4-mm expansion shells (S1 and S2) were created, generating 2 ROIs and 2 contralateral controls. Fractional anisotropy and regional homogeneity measurements were then extracted from each ROI and compared with the contralateral controls. Reliability, accuracy, and precision were compared as appropriate. RESULTS: Fifty-four patients were identified and included. Errors of fractional anisotropy were significantly lower than those of regional homogeneity in S1 and S2 (P < .001), suggesting that fractional anisotropy is more reliable than regional homogeneity near cerebral cavernous malformations. Proximity to cerebral cavernous malformations worsened the reliability of regional homogeneity (S1 versus S2, P < .001), but not fractional anisotropy (P = .24). While fractional anisotropy was not significantly biased in any ROI (P > .05), regional homogeneity was biased toward lower signals in S1 and S2 (P < .05), an effect that was attenuated with distance from cerebral cavernous malformations (P < .05). Fractional anisotropy measurements were also more precise than regional homogeneity in S1 and S2 (P < .001 for both). CONCLUSIONS: Our findings suggest that hemosiderin-rich lesions such as cerebral cavernous malformations may lead to artifactual depression of fMRI signals and that clinicians and surgeons should interpret fMRI studies near cerebral cavernous malformations with caution. While fMRI is considerably affected by cerebral cavernous malformation-related artifacts, DTI appears to be relatively unaffected and remains a reliable imaging technique near cerebral cavernous malformations.

Correlations between cervical spinal cord magnetic resonance diffusion tensor and diffusion kurtosis imaging metrics and motor performance in patients with chronic ischemic brain lesions of the corticospinal tract.

PURPOSE: To investigate modifications of Magnetic Resonance Diffusion Tensor Imaging (DTI) and Diffusion Kurtosis Imaging (DKI) metrics in lateral white matter (WM) bundles of the cervical spinal cord in patients with previous stroke in the vascular territory of the middle cerebral artery (MCA). METHODS: Twenty consecutive patients with a previous ischemic stroke of the MCA territory and a varying degree of upper motor impairment were enrolled. DKI was centered at the C3C4 and C5C6 intervertebral level. RESULTS: The fractional anisotropy (FA) values in C3C4 and C5C6 were found to be significantly lower in the lateral WM bundles contralateral to the ischemic lesion and thus, in the WM bundle including the affected corticospinal tract (CST) (p = 0.005 and p = 0.008, respectively), as well as mean kurtosis (MK) and axonal water fraction (AWF) values (p = 0.004 and p = 0.04. respectively). FA values correlated significantly with the Global Motor Index (GMI) both for C3C4 (ρ = 0.61, p = 0.004) and C5C6 (ρ = 0.69, p = 0.002). At C3C4, AWF correlated significantly with GMI (ρ = 0.54, p = 0.03). No correlations were found between lateral WM bundle volumes and GMI. CONCLUSION: A reduction of anisotropy and microstructural complexity in the affected lateral WM bundle of the cervical spinal cord was observed in patients with previous ischemic stroke involving the CST. The correlations between these metrics and motor performance were statistically significant.

Spinal cord microstructure integrating phase-sensitive inversion recovery and diffusional kurtosis imaging.

PURPOSE: The aim of this prospective study was to determine the feasibility in terms of repeatability and reproducibility of diffusional kurtosis imaging (DKI) for microstructural assessment of the normal cervical spinal cord (cSC) using a phase-sensitive inversion recovery (PSIR) sequence as the anatomical reference for accurately defining white-matter (WM) and gray-matter (GM) regions of interests (ROIs). METHODS: Thirteen young healthy subjects were enrolled to undergo DKI and PSIR sequences in the cSC. The repeatability and reproducibility of kurtosis metrics and fractional anisotropy (FA) were calculated in GM, WM, and cerebral-spinal-fluid (CSF) ROIs drawn by two independent readers on PSIR images of three different levels (C1-C4). The presence of statistically significant differences in DKI metrics for levels, ROIs (GM, WM, and CSF) repeatability, reproducibility, and inter-reader agreement was evaluated. RESULTS: Intra-class correlation coefficients between the two readers ranged from good to excellent (0.75 to 0.90). The inferior level consistently had the highest concordance. The lower values of scan-rescan variability for all DKI parameters were found for the inferior level. Statistically significant differences in kurtosis values were not found in the lateral white-matter bundles of the spinal cord. CONCLUSION: The integration of DKI and PSIR sequences in a clinical MR acquisition to explore the regional microstructure of the cSC in healthy subjects is feasible, and the results obtainable are reproducible. Further investigation will be required to verify the possibility to translate this method to a clinical setting to study patients with SC involvement especially in the absence of MRI abnormalities on standard sequences.

Altered Kv2.1 functioning promotes increased excitability in hippocampal neurons of an Alzheimer's disease mouse model.

Altered neuronal excitability is emerging as an important feature in Alzheimer's disease (AD). Kv2.1 potassium channels are important modulators of neuronal excitability and synaptic activity. We investigated Kv2.1 currents and its relation to the intrinsic synaptic activity of hippocampal neurons from 3xTg-AD (triple transgenic mouse model of Alzheimer's disease) mice, a widely employed preclinical AD model. Synaptic activity was also investigated by analyzing spontaneous [Ca(2+)]i spikes. Compared with wild-type (Non-Tg (non-transgenic mouse model)) cultures, 3xTg-AD neurons showed enhanced spike frequency and decreased intensity. Compared with Non-Tg cultures, 3xTg-AD hippocampal neurons revealed reduced Kv2.1-dependent Ik current densities as well as normalized conductances. 3xTg-AD cultures also exhibited an overall decrease in the number of functional Kv2.1 channels. Immunofluorescence assay revealed an increase in Kv2.1 channel oligomerization, a condition associated with blockade of channel function. In Non-Tg neurons, pharmacological blockade of Kv2.1 channels reproduced the altered pattern found in the 3xTg-AD cultures. Moreover, compared with untreated sister cultures, pharmacological inhibition of Kv2.1 in 3xTg-AD neurons did not produce any significant modification in Ik current densities. Reactive oxygen species (ROS) promote Kv2.1 oligomerization, thereby acting as negative modulator of the channel activity. Glutamate receptor activation produced higher ROS levels in hippocampal 3xTg-AD cultures compared with Non-Tg neurons. Antioxidant treatment with N-Acetyl-Cysteine was found to rescue Kv2.1-dependent currents and decreased spontaneous hyperexcitability in 3xTg-AD neurons. Analogous results regarding spontaneous synaptic activity were observed in neuronal cultures treated with the antioxidant 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox). Our study indicates that AD-related mutations may promote enhanced ROS generation, oxidative-dependent oligomerization, and loss of function of Kv2.1 channels. These processes can be part on the increased neuronal excitability of these neurons. These steps may set a deleterious vicious circle that eventually helps to promote excitotoxic damage found in the AD brain.

Diffusion tensor imaging of subependymal heterotopia.

A magnetic resonance (MR) diffusion tensor imaging (DTI) study was performed in a newborn with bilateral subependymal heterotopia (SE). White matter fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD) were compared to values obtained in four newborns with moderate perinatal asphyxia and normal MRI findings. The reduction of FA and increase of AD and RD in the newborn with SE were the in vivo late expression of alterations in the intermediate zone, with an underlying arrest of neuronal migration.

Pigmentaciones ungueales: diagnóstico dermatoscópico / Nail pigmentation: dermoscopic examination

Las pigmentaciones longitudinales de las uñas son un problema común en la práctica dermatológica diaria y suponen un reto diagnóstico. El diagnóstico diferencial es muy amplio abarcando desde hematomas subungueales, infecciones fúngicas, hasta lesiones melanocíticas (léntigo, nevus, melanoma)entre otros. Las pigmentaciones de la lámina ungueal pueden ser secundarias a lesiones sobre la matriz ungueal, que es el tejido germinativo de la uña. De todas las lesiones originadas en la matriz, el melanoma ungueal es nuestra principal preocupación ya que, aunque es infrecuente, ya que supone aproximadamente el 1% de los melanomas cutáneos, es un tumor agresivo y destructor y de su diagnóstico precoz depende su pronóstico. Los dermatólogos a menudo dudamos del diagnóstico clínico y del manejo de las pigmentaciones ungueales. Además suele haber reticencia por hacer biopsias de la matriz debido a que es un proceso doloroso que puede provocar distrofias ungueales permanentes. La dermatoscopia indirecta a través de la lámina ungueal ofrece criterios adicionales a la clínica que facilitan el diagnóstico diferencial de las lesiones. El objetivo de este artículo es revisar la semiología dermatoscópica para facilitar el diagnóstico diferencial y el manejo de las pigmentaciones ungueales (AU)

Longitudinal pigmentation of the nails are a common problem in daily dermatology practice as well as a diagnostic challenge. The differential diagnosis is wide ranging from subungual hematoma, fungal infections, to melanocytic lesions (lentigo, nevus, melanoma), among others. The pigmentation of the nail plate may be secondary to injury of the nail matrix, which is the germinative tissue of the nail. Of all the injuries caused in the matrix, the nail melanoma is our main concern that, although uncommon, is presented approximately in 1% of cutaneous melanoma. Nail melanoma is also an aggressive and destructive tumor and its prognosis depends on the early diagnosis. Dermatologists often doubt on the clinical diagnosis and management of nail pigmentations. In addition there are often avoid to take biopsies of the matrix because it is a painful process that can cause permanent nail dystrophy. Dermoscopy through the nail plate provides additional criteria to the clinic to facilitate the differential diagnosis of lesions. The aim of this paper is to review the dermoscopic semiology to facilitate differential diagnosis and management of nail pigmentations (AU)

Xantomatosis normolipémica y reumatismo palindrómico / Normolipidemic xanthomatosis and palindromic rheumatism

Los xantomas son una forma común de presentación cutánea de las alteraciones del metabolismo de los lípidos y generalmente indican (..) (AU)

Xanthomas are common cutaneous presentation of disorders of (..) (AU)

Lichen Sclerosus et Atrophicus with Cutaneous Distribution Simulating Lichen Planus.

Lichen sclerosus (LS) et atrophicus is a disease of unknown etiology, although hereditary, endocrine, and autoimmune factors are known to be involved. While the anal and genital regions are predominantly affected, only 2.5% of patients present with extragenital lesions, particularly of the trunk, neck, and upper limbs. The possible relationship between lichen sclerosus et atrophicus and both lichen planus (LP) and localized scleroderma (morphea) has not been clearly established, although in a number of cases, several of these conditions have been found simultaneously. We report the case of a 31-year-old woman with LS lesions affecting the neck, upper back, wrist and dorsum of the feet. The unusual character of this presentation is pointed out, along with its clinical similarity to LP.

[Lever's facial granuloma. Study using direct immunofluorescence in 2 cases]. / Granuloma facial de Lever. Estudio con inmunofluorescencia directa en dos casos.

Cases of two 48 and 55 year-old males affected of facial granuloma with eosinophilia are presented. In both cases direct immunofluorescence studies revealed the presence of IgG, IgA and C3 along the basement membrane. A brief comments on clinical and histological appearance, previous immunofluorescence studies, pathogenesis and treatment are made.